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The aim of this study was to determine the levels of Na, K, Ca, Mg, Fe, Zn, Cu, Pb and Cd in the muscle, liver and gills of roach (Rutilus rutilus) and perch (Perca fluviatilis) from three polymictic and eutrophic lakes in poor ecological condition in north-western Poland. Metals in the waters of the lakes, as well as in the muscle, gills and livers of fish, were determined by atomic absorption. Oxygen deficits in summer and high concentrations of Cd and Pb were responsible for the low water quality of the lakes studied. Perch and roach showed a potential to accumulate metals from the water (bioconcentration factor >1). The lowest concentrations of Na, Fe, Zn, Cu, Pb and Cd were found in the fish muscle. The highest concentrations of Cd and Pb were recorded in the liver of both species. Differences in metal concentration between the species were mainly due to significantly higher levels of Fe, Cu and Zn in the muscle of the roach than in the perch (p

American mink Neovison vison is one of the most harmful non-indigenous species in Iceland and has been proven to be a useful indirect bioindicator and biomonitor for numerous environmental pollutants. Therefore, the main objective of the study was to determine the total nickel concentration in the spleen of 35 females and 30 males obtained from Brokey archipelago and the south coast of Hvammsfjörður (Dalabyggð, Iceland) using graphite furnace atomic absorption spectroscopy. We also assessed the correlation between nickel concentration and selected anatomical and morphological parameters, hypothesising that invasive alien N. vison is a promising candidate species for biomonitoring the deposition of this trace element. The results indicated a substantial variation in nickel concentration in the spleen tissue of examined animals. For males, the maximum concentration exceeded the average level by more than 16 times, and for females by more than 7 times. The correlation coefficient between morphometric features and the level of nickel concentration in the spleen did not show a significant relationship in any of the tested combinations, for all tested animals or for each sex separately. In conclusion, American mink in Iceland can be considered a promising species for qualitative and quantitative assessment of ecosystems in terms of nickel pollution.

Membrane separation systems have been used in process industry since decades; however, their designs are based mainly on experienced-based and use of trial-and-error approach, especially in case of membrane selection. This chapter reviews recent advancements in the design of membrane systems used either for separation or creation of mixtures from the perspective of industry 4.0 and data management. Additionally, computer-aided design tools have been reviewed with aim of possible use in the design of membrane separation systems.

Analysis of the physicochemical properties of fresh eggs (raw material for caviar production) of the Salmonidae [sea trout (Salmo trutta L. 1758) and rainbow trout (Oncorhynchus mykiss, Walbaum 1792)] and the acipenseridae [siberian sturgeon (Acipenser baeri Brandt, 1869)], as well as sturgeon hybrids (Acipenser baeri Brandt, 1869 × Acipenser gueldenstaedti Brandt & Ratzeburg, 1833), included determination of basic physicochemical parameters (pH, dry weight, content of protein, fat, fiber and ash), amino acid composition and fatty acid profile. Compared to the Acipenseridae, Salmonidae eggs yielded a 22.5% higher total protein content, a 40.0% higher level of essential amino acids (EAA) and a 57.5% lower crude fat content. The sea trout eggs showed also a completely different fatty acids profile and hence values of lipid indices (lowest PUFA value – 11.72%, highest SFA value – 39.86%). The rainbow trout and sturgeon eggs had a similar fatty acid profile, and were characterized by a high nutritional and dietary value.

The ichthyological biodiversity of Polish lakes is poorly understood, even in lakes not used for fishing and those under strict protection. With this in mind, the aim of this study was to conduct a comprehensive ichthyological survey of several lakes in the Wolin National Park (Poland). The study was conducted in Domysławskie and Gardno lakes and the anthropogenic Stara Kredownia reservoir. Each fishing exercise was conducted using benthic nets over a 12 h period. The fish caught were measured and weighed, and the species identified. Shannon-Wiener (H) and Simpson biodiversity indices were determined. The catch comprised a total of 4580 fish (of which 4391 were caught in Domysławskie Lake) belonging to 15 species, with a combined weight of 98,165 g. In general, the most prevalent species were non-predatory fish: roach (Rutilus rutilus), freshwater bream (Abramis brama), white bream (Blicca bioerkna), bleak (Alburnus alburnus), and rudd (Scardinius erythrophthalmus). Individually, perch (Perca fluviatilis) and roach (Rutilus rutilus) were the most abundant species. Ichthyofauna diversity varied greatly between the studied water bodies, with 15 species found in Domysławskie Lake and only 6 species in Gardno Lake. In Stara Kredownia Reservoir, no fish were caught, but amphibians were observed, such as great crested newts (Triturus cristatus) and common newts (Lissotriton vulgaris). Based on the results obtained, Lake Domysławskie had a higher species ichthyofauna diversity than the other ‘tench and pike’ lakes. Gardno Lake had a much lower biodiversity.

The health benefits and detrimental effects of coffee consumption may be linked to chemical compounds contained in coffee beans. The aim of our study was to evaluate the concentration of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), copper (Cu), zinc (Zn), aluminum (Al), nickel (Ni), lead (Pb) and cadmium (Cd) in green and roasted samples of coffee beans purchased in Bosnia and Herzegovina, and to determine the potential health implications at current consumption level.The concentrations were determined using a microwave high-pressure mineralization and atomic absorption spectrometer that measures total metal (ionic and non-ionic) content.The average metal concentrations (μg element/g coffee) in the green coffee beans were; Na: 18.6, K: 19898, Ca: 789, Mg: 1758, Fe: 60, Cu: 14, Zn: 3.6, Al: 4.2, Ni: 0.415, Pb: 0.076, and Cd: 0.015, while, in the roasted; Na: 23, K: 23817, Ca: 869, Mg: 1992, Fe: 41.1, Cu: 11.4, Zn: 5.41, Al: 4.19, Ni: 0.88, Pb: 0.0169, and Cd: 0.0140.The level of investigated metals at the present level of consumption of coffee in Bosnia falls within the limits recommended as safe for health.Zdravstvene prednosti in škodljivi učinki uživanja kave so lahko povezani z kemijskimi spojinami v kavnih zrnih. Cilj študije je oceniti koncentracije naslednjih spojin: natrij (Na), kalij (K), kalcij (Ca), magnezij (Mg), železo (Fe), baker (Cu), cink (Zn), aluminij (Al), nikelj (Ni), svinec (Pb) in kadmij (Cd) v zelenih in praženih vzorcih kavnih zrn, kupljenih v Bosni in Hercegovini, ter določiti morebitne zdravstvene posledice glede na trenutno raven uživanja.Koncentracije so bile določene z uporabo visokotlačne mineralizacije z mikrovalovi in atomske absorpcijske spektrometrije, ki merijo skupno vsebino kovine (ionska in neionska).Povprečna koncentracija kovin (μg elementa/g kave) v zelenih kavnih zrnih je bila: Na: 18,6, K: 19898, Ca: 789, Mg: 1758, Fe: 60, Cu: 14, Zn: 3,6, Al: 4,2, Ni: 0,415, Pb: 0,076 in Cd: 0,015; v praženih zrnih pa: Na: 23, K: 23817, Ca: 869, Mg: 1992, Fe: 41,1, Cu: 11,4, Zn: 5,41, Al: 4,19, Ni: 0,88, Pb: 0,0169 in Cd: 0,0140.Raven preverjenih kovin na trenutni stopnji uživanja kave v Bosni in Hercegovini se nahaja znotraj omejitev, ki so priporočene kot zdrave za zdravje.

Chinese mitten crab (Eriocheir sinensis) is a valued foodstuff in China. However, their elemental composition is still poorly understood. Therefore, the aim of this study was to quantify the concentrations of Al, As, Ca, Cd, Cu, Fe, K, Mg, Na, Ni, Pb, Se, and Zn in muscle, hepatopancreas, gonads, gills, and exoskeletons of E. sinensis caught in spring and autumn in the Szczecin Lagoon, and to compare these levels to Dietary Reference Intake. High levels of Ca (>20, 000 μg g−1) in the exoskeleton, K (5,980 μg g−1) and Zn (80.8 μg g−1) in muscle, Ni (0.678 μg g−1) and Cd (0.3278 μg g−1) in the hepatopancreas, As (0.0411 μg g−1) and Se (0.3208 μg g−1) in the gonads, Fe (204 μg g−1), Cu (59.0 mg g−1), and Pb (0.0742 mg g−1) in the gills were measured. The edible parts of E. sinensis caught in Poland can be a valuable source of macro- and microelements important in human diet. Levels of Pb and Cd did not exceed the established food safety level of 0.50 μg g−1. The results showed that introduction of commercial fishing of this species may be profitable and would also comply with the European Union's legal regulations concerning the reduction of invasive animal populations in Europe.

The aim of the study was to investigate the effect of iron coagulant (IC), aluminum coagulant (AC) and lanthanum modified bentonite (LMB) on the embryogenesis of pike. Physicochemical indicators of the water were determined according to the methods recommended by APHA (1999). The applied precipitating agents (IC, AC, LMB) at appropriate concentrations were sprayed on the surface of water in aquariums with the pike eggs placed on nets. The eggs were observed under a microscope, documenting their development using digital photography NIS Elements Br software. The number of fertilized eggs, embryo survival, and the percentage of malformed larvae were determined. The pike eggs and hatched larvae were recorded and measured. The percentage of fertilized eggs was found to be the highest in the control sample (LW) and in the IC sample (94% and 93.3%, respectively), 85.9% in the AC sample and 81.8% in the LMB sample. The pace of pike embryogenesis in the samples was identical – the embryos in both the control and other samples reached individual stages of embryonic development with an equal number of degree days (DD). The IC group hatched the earliest, and the control sample was the last to hatch (LW). In the control sample, the hatched larvae were the longest and had the lowest percentage of malformed individuals. The control sample also had the highest rate of embryo survival (85.9%), while the lowest was in the LMB sample (68.6%). These results indicate that the application of precipitating measures to improve water quality should not coincide with the periods of fish reproduction.

Although interest in the use of membranes for the concentration of microalgal biomass has steadily been growing, little is known regarding the phenomena of membrane fouling. In addition, more attention has been given to polymeric membranes compared to ceramic membranes, which have a longer life that is associated with a higher resistance to aggressive chemical cleaning. In this study, microfiltration (MF) and ultrafiltration (UF) of two microalgae species, Chlorella vulgaris and Monoraphidium contortum, were carried out using tubular crossflow ceramic membranes. Permeate flux was measured, resistance was calculated, and dissolved organic carbon (DOC) was determined. The flux reduction during the first 10 min of filtration was higher for MF than UF (>70% and 80%) than for MF (

The aim of the study was to present a comprehensive characterisation of crayfish meat, which is crucial to assess its potential usefulness in the food industry. To this end, we assessed the yield, basic chemical composition (protein, fat, minerals), nutritional value (amino acid and fatty acid profiles, essential amino acid index (EAAI), chemical score of essential amino acids (CS), hypocholesterolaemic/hypercholesterolaemic ratio (h/H), atherogenicity (AI) and thrombogenicity (TI) indices), as well as culinary value (lab colour, texture, sensory characteristics, structure) of the meat of spiny-cheek crayfish (Faxonius limosus) (n = 226) from Lake Sominko (Poland) harvested in May&ndash, September 2017. Crayfish meat, especially that from the abdomen, was shown to have high nutritional parameters. It is lean (0.26% of fat), with a favourable fatty acid profile and a very high quality of fat (PUFA (sum of polyunsaturated fatty acids):SFA (sum of saturated fatty acids), n-6/n-3, h/H, AI, TI) and protein (high CS and EAAI). It is also a better source of Ca, K, Mg, Na, P, and Cu than meat from slaughter animals. Hence, crayfish meat can be an alternative to livestock meat in the human diet. Owing to its culinary value (delicateness, weak game flavour, and odour), it meets the requirements of the most demanding consumers, i.e., children and older people.

Simple Summary Freshwater crayfish species are critical for both local communities and the modern food industry. The study characterised the meat of invasive spiny-cheek crayfish, analysing the yield, basic chemical composition, nutritional value, as well as culinary value. Crayfish meat has high nutritional parameters due to favourable fatty acid and amino acid profiles, as well as balanced mineral content. Crayfish meat is an alternative to livestock meat in the human diet and draws attention of the food industry to the processing of underutilised resources of high-quality aquatic species. Abstract The aim of the study was to present a comprehensive characterisation of crayfish meat, which is crucial to assess its potential usefulness in the food industry. To this end, we assessed the yield, basic chemical composition (protein, fat, minerals), nutritional value (amino acid and fatty acid profiles, essential amino acid index (EAAI), chemical score of essential amino acids (CS), hypocholesterolaemic/hypercholesterolaemic ratio (h/H), atherogenicity (AI) and thrombogenicity (TI) indices), as well as culinary value (lab colour, texture, sensory characteristics, structure) of the meat of spiny-cheek crayfish (Faxonius limosus) (n = 226) from Lake Sominko (Poland) harvested in May–September 2017. Crayfish meat, especially that from the abdomen, was shown to have high nutritional parameters. It is lean (0.26% of fat), with a favourable fatty acid profile and a very high quality of fat (PUFA (sum of polyunsaturated fatty acids):SFA (sum of saturated fatty acids), n-6/n-3, h/H, AI, TI) and protein (high CS and EAAI). It is also a better source of Ca, K, Mg, Na, P, and Cu than meat from slaughter animals. Hence, crayfish meat can be an alternative to livestock meat in the human diet. Owing to its culinary value (delicateness, weak game flavour, and odour), it meets the requirements of the most demanding consumers, i.e., children and older people.

The separation efficiencies of aqueous solutions containing nitric salts of Zn, Cu, Fe or Pb at various pH in process of nanofiltration have been investigated experimentally. These results were used to obtain the total volume membrane charge densities, through mathematical modelling based on the Donnan&ndash, Steric partitioning Model. The experimentally obtained retention values of individual heavy metal ions varied between 36% (Zn2+ at pH = 2), 57% (Pb2+ at pH = 2), 80% (Fe3+ at pH = 9), and up to 97% (Cu2+ at pH = 9). The mathematical modelling allowed for fitting the total volume membrane charge density (Xd), which yielded values ranging from &minus, 451.90 to +900.16 mol/m3 for different non-symmetric ions. This study presents the application of nanofiltration (NF) modelling, including a consideration of each ion present in the NF system&mdash, even those originating from solutions used to adjust the pH values of the feed.

An annual assessment of the functioning of the filter systems filled with polypropylene and gravelite profiles, located in the river bed, to reduce total suspensions and biogenic compounds in the water before it was directed to the city lake was carried out. It has been shown that, due to poor maintenance and a small number of cleaning operations, the efficiency of the system has decreased considerably comparing to the period of correct operation. This was mainly related to the exhaustion of the ability to retain the main biogenic element – phosphorus. During the monitoring period the facility retained the ability to reduce organic pollutants, suspended solids and nitrogen.

Livestock farming, in addition to numerous benefits, has a number of negative effects on the environment, including the emissions of pollutants, incl. odorants, to atmospheric air. The purpose of the work was to characterize the methods used in assessing the emission of odours from breeding facilities and to analyze the odor standards used in the global legal regulations. The values of odour concentrations measured in livestock buildings and the emission values estimated on the basis of emission factors for various types of livestock farming are presented in the paper. The analyses show that the legal system of European countries applies odour standards expressed in European odour units for a specific unit of time per one animal position (ouE/s/animal place). The analysis of odour concentration measurements and calculations of odour emission factors carried out for poultry farms (turkeys and broilers), pig farms and fur farms showed the highest values of odour emissions for a swine farm and the highest calculated odour emission rates for weaners and sows, which is in line with the values of odor emission indicators suggested by the EU.

In this study we analyzed the composition of post-production marinating brines (MB) from the marination of fresh and frozen herring in marinating brines comprising 6–10% NaCl and 3–4% acetic acid. After 7 days of marination in a 1-step or 2-step marinating process, NaCl levels in MB decreased by ∼33% and acetic acid by ∼60% compared to fresh marinating brine. The post-production marinating brines contained NaCl (37–43 g/dm 3 ), acetic acid (14–18 g/dm 3 ), total dry matter (64–73 g/dm 3 ), fat (5–27 g/dm 3 ), and protein (14–26 g/dm 3 ). Their turbidity was in the range of 307–2427 NTU, while pH The recovery of protein, fat, and purified marinating brine was tested in a cascade membrane system, using microfiltration (polypropylene bag 25 μm) and ultrafiltration (UF) performed with ceramic membranes with cut-offs of 150 kDa and 1 kDa. In the permeate we observed no changes in pH, NaCl and acetic acid levels; it was clear (turbidity at 1 NTU) and sterile. The permeate recovery coefficient was 0.50, and its reuse can reduce the use of NaCl and acetic acid in the production of marinating brines by about 20–25%. The highest rejection coefficient for protein content (average 0.30) and fat content (from 0.66 to 1.00) was observed for the membrane with a cut-off of 150 kDa. Overall recovery after both stages of UF was 0.60 for total protein and 0.40–0.69 for total fat. In conclusion, the tested membrane system recovered biomolecules (protein and fat) and the permeate. This makes it an alternative technical solution thanks to which post-production marinating brine may be re-used and not just discharged as effluent.

The Chinese mitten crab ( Eriocheir sinensis ) is an invasive species in the Baltic Sea catchment area. Its numbers in fishery are steadily growing and can potentially become a considerable export product. However, the meat of these crustaceans is known to accumulate contaminants, such as trace elements. Therefore, in this study we examined the content of Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, U, Zn in the claws, legs, and carapace of Chinese mitten crabs from Lake Dąbie (south-western catchment area of the Baltic Sea). Concentrations of Mo and U were within the sensitivity limit of the analytical method, and the average concentrations (in mg kg −1 dw) of the remaining elements ranged from 0.016 (Cd, claw meat) to 191 (Fe, carapace). The meat had very high concentrations of essential metals (Fe > 20, Cu > 17, Zn > 16, Mn > 2, in mg kg −1 dw). The concentrations of Pb and Cd were 5 and 100 times lower than the threshold for foods established by the Commission Regulation (EC) No 1881/2006. The meat of crabs from Lake Dąbie should be safe for consumers and may be a source of elements playing important functions in metabolic processes.

Signal crayfish (Pacifastacus leniusculus) is an invasive species displacing native European crayfish from their natural habitats. The elemental composition of the population from the southern Baltic coastal river and the potential health hazards are not known. The aim of the conducted research was to assess the quantitative content of Al, As, Ca, Cd, Cu, Fe, K, Mg, Na, Ni, Pb, Se, and Zn in meat, hepatopancreas, and exoskeleton in a population from Wieprza River (Poland) and compare the results with the recommendations of daily human consumption. Analysis also involved the composition of water and sediments. The concentrations of elements were analyzed using an Atomic Absorption Spectrometer. The bioconcentration factor (BCF) of elements in the signal crayfish was much higher from water than from sediments. Bioaccumulation of elements differed between the particular parts of the body of crayfish, e.g., Ca showed extreme predominance in the exoskeleton, while in meat exhibited a predominance of K, Na, Ca, and Mg. Among trace elements, crayfish meat was the richest in Zn, Cu, and Fe. The concentrations of non-essential Cd, Pb, and As were low compared to other determined elements. The highest concentrations of As, Cd, Cu, Fe, Ni, and Se were found in the hepatopancreas, while the highest levels of Al and Pb were found in the exoskeleton. Generally, it was found that the meat of P. leniusculus can be a perfect supplement to the human diet, and the consumption of 100 g of meat per day did not exceed the dietary reference values for essential elements and also for Al, As, Cd, Ni, and Pb.

In this study, we determined the levels of essential and non-essential elements in the Harris mud crab (Rhithropanopeus harrisii, Maitland, 1874) from the southern Baltic Sea. Results revealed high levels of Ca (246,000 ppm), Mg (11,000 ppm), Na (8160 ppm), K (3,780 ppm), and Fe (1830 ppm). The concentrations of essential metals such as Zn (62.5 ppm) and Cu (25 ppm) were similar to those recorded in other crab species. The concentrations of non-essential metals such as Pb (0.140 ppm), Cd (0.0017 ppm), and As (0.288 ppm) were well below the International Standards for Maximum Levels for Food. In view of the above, the Harris mud crab from the southern Baltic is safe to be used as a component of well-balanced feeds for terrestrial and aquatic animals.

The Chinese mitten crab (Eriocheir sinensis) is an invasive species in Europe. This study aimed to determine the levels of Al, As, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Se, and Zn in the muscles and hepatopancreas of female and male and in the gonads of females caught in the Elbe River (Germany), relative to water and sediment levels, using an atomic absorption spectrometer. Elemental levels were compared with the Dietary Reference Intakes (DRI). The results showed that females had significantly higher muscle levels of Cr and Zn than the males, and males had significantly higher hepatopancreas levels of Cd, Se, and Co. Generally, the hepatopancreas had significantly higher levels of most elements than the gonads and muscles. Levels of Cu, Fe, and Zn exceeded the Recommended Dietary Allowances. The levels of all the elements were below the Tolerable Upper Intake Level, and Tolerable Daily Intakes for Pb, Cd, Cr, Co, and As were not exceeded. In conclusion, the edible parts of the crabs can be an excellent supplement to the human diet, and the intake of 100 g portions a day will not exceed DRI for the studied elements.

The molecular weight of proteins and protein hydrolysis products (PHP) in the fractionated postproduction marinating brines left after herring marination process was determined by the HPLC. The proteins and PHP retention was evaluated in the three-stage purification process with the usage of polypropylene bag (25 μm) and ceramic membranes with the cut-off of 150 and 1 kDa. It was found that the process of marination contributes to high participation of compounds in the post-production marinating brines. Those are characterised by low molecular weight, formed as a result of protein hydrolysis. Each stage of the scavenging process was reducing the content of proteins and PHP. The lowest retention was observed in the stage at which a PP bag was used, while the highest in the UF process, with the usage of 150 kDa membrane. The total retention of proteins and PHP differed according to the type of post-production marinating brines and reached the level of 16-22%.

The aim of the study was to analyze and assess the possibility of using a two-stage filtration system with ceramic membranes: a 3-tube module with 1.0 kDa cut-off (1st stage) and a one-tube module with 0.45 kDa cut-off (2nd stage) for treating effluent water from a juvenile African catfish aquaculture. The study revealed that during the 1st filtration stage of the effluent water, the highest degrees of retention were obtained with respect to: suspended solids SS (rejection coefficient RI=100%), turbidity (RI=99.40%), total iron (RI=89.20%), BOD5 (RI=76.0%), nitrite nitrogen (RI=62.30%), and CODCr (RI=41.74%). The 2nd filtration stage resulted in a lower reduction degree of the tested indicators in comparison to the 1st filtration stage. At the 2nd stage, the highest values of the rejection coefficient were noted in for the total iron content (RIV=100%), CODCr (RIV=59.52%; RV=64.28%, RVI=63.49%) and turbidity (RIV and RV = 45.0%, RVI=50.0%). The obtained results indicate that ceramic membranes (with 1.0 and 0.45 kDa cut-offs) may be used in recirculation aquaculture systems as one of the stages of effluent water treatment.

The aim of this study was to assess the effect of a fish hatchery (Stocking-Breeding Centre in Goleniów -OHZ), focused on the production and on-growing of stocking material, on the quality of post-production water. The following parameters were determined: dissolved oxygen, organic matter content, buffering capacity, the concentration of some forms of nitrogen and phosphorus ((N-NH4+, N-NO2–, N-NO3-, total nitrogen, P-PO43-, total phosphorus) and the concentration of chloride ions. The study also included the measurements of water temperature, electrolytic conductivity and pH. It was shown that the water supplied to the hatchery had good quality, providing optimum conditions for growth and living of fry and juvenile forms of various fish species (most indices were within the range of the first water quality class). Production activities at the hatchery caused a reduction in the quality of discharged post-production water with respect to indicators such as total suspended solids, organic matter and phosphorus.

Spiny-cheek crayfish (Faxonius limosus, Rafinesque, 1817) females and males were examined as an alternative source of highly valuable material currently sought by the food industry. The aim of the study was to assess the profiles of 14 macro- and microelements (Al, Ca, Cd, Cu, Fe, K, Mg, Na, Ni, P, Pb, Se, Si, Zn) in the meat, exoskeleton and eggs (females) of crayfish collected in the spring and autumn seasons in the Lake Sominko (Poland). The content of heavy metals was analysed, and the degree of their accumulation in crayfish tissues was determined. The profile of the investigated elements in the tested samples was variable depending on the body part, sex of individuals and season of sample collection. A portion of crayfish abdomen meat or eggs (100 g) is particularly rich in P (41.5–73.9 %) of daily requirement), Zn (14.1–38.5 %), Mg (7.9–21.5 %), K (3.3–13.1 %) and Na (4.6–7.7 %) and small quantities of Ca (0.8–2.5 %) and Al (0.9–4.7 %). The study confirmed that consumption of crayfish meat is toxicologically safe and nutritionally complete.

Effective protection of lakes against degradation requires a detailed recognition of the factors leading to their eutrophication. This also pertains to small lakes, which constitute an important element of various ecosystems and are crucial for maintaining biodiversity. Therefore, the aim of the study is to determine the trophic state as well as the susceptibility to degradation of three small lakes in north-western Poland: Maszewo, Starzyca, and Nowogardzkie. This study analyzes the morphometric characteristics of the lakes, the impact of the catchment, their actual trophic state, and phosphorus levels. The analysis showed varying regeneration potentials of the lakes. Maszewo Lake is eutrophic-hypertrophic, nonresilient, strongly exposed to influence from the catchment, with phosphorus levels within the norm. Starzyca Lake is a eutrophic lake, not very resilient to the influence of the catchment, with excessive phosphorus levels. Nowogardzkie Lake is a eutrophic lake with moderate resilience to degradation, but with excessive phosphorus levels, which endangers the functioning of this aquatic ecosystem. In all the lakes, phosphorus supply was predominantly internal. Restoration of these lakes could be performed by completely cutting off the inflow of nutrients, as well as reclamation involving the deactivation of phosphorus (e.g., by precipitation) as well as the removal of the bottom sediments responsible for the internal supply of phosphorus.

Environmental pollution with heavy metals is a serious global issue. In order to meet increasingly stringent environmental regulations, new technologies for the elimination and/or recovery of heavy metals from wastewater are tested and implemented. These technologies include membrane separations like reverse osmosis (RO), ultrafiltration (UF) and nanofiltration (NF). Direct and combined techniques have been discussed: BSA-enhanced nanofiltration, micellar enhanced ultrafiltration (MEUF) and polyelectrolyte enhanced ultrafiltration (PEUF). Membrane techniques allow for a high elimination of heavy metals, comparable to currently used technologies such as chemical precipitation, coagulation, flotation, or ion exchange.

The present study was carried out to investigate the possibility of using ceramic membranes for microalgal biomass densification and to evaluate the qualitative composition of the permeate as a source of nitrogen and phosphorus for microalgae cultivated in a closed system. The studies were conducted on the microalga Monoraphidium contortum. The microfiltration process was carried out on a quarter-technical scale using ceramic membranes with 1.4 μm, 300 and 150 kDa cut-offs. Permeate flux and respective hydraulic resistances were calculated. Dissolved inorganic nitrogen and phosphorus fractions were measured in the feed and the permeate. It was noted that the permeate flux in the MF process was decreasing while the values of reversible and irreversible resistances were increasing as the cut-off of the studied membranes was diminishing. An analysis of the hydraulic series resistance showed that using a 300 kDa membrane would be the most beneficial, as it was characterized by a comparatively high permeate flux (Jv=1.68 10(-2)m(3)/m(2)s), a comparatively low susceptibility to irreversible fouling (1.72·10(9) 1/m) and a high biomass retention coefficient (91%). The obtained permeate was characterized by high concentrations of dissolved nitrogen and phosphorus forms, which indicated that it could be reused in the process of microalgal biomass production.

One of the alternative wastewater treatment methods aimed at the elimination of heavy metals is membrane separation supported by the use of metal-complexing polymers. Many sectors of industry generate wastewater containing both heavy metals and protein substances which show complex-forming properties. In this study, a 450 Da molecular weight cut-off nanofiltration ceramic membrane (TAMI Industries, France) was tested to evaluate the retention of Zn, Cd, Pb, Cu and Fe complexed with bovine serum albumin (BSA). Retention levels were tested in water solutions solely for the metals and for the metals with the addition of BSA, depending on the pH of the solutions (from 2.0 to 9.0). It was noted that the retention tended to increase as the pH increased. For solutions composed with only metals, retentions exceeding 80% were noted for pH > 6.9. The addition of a complexing agent resulted in high retentions of Cu, Cd and Zn already at pH = 2.0. Maximum retentions for Zn, Cd, Pb, Cu and Fe were noted for solutions containing the mixture of metals and BSA at pH = 6.0 (97, 96, 90, 95 and 71%, respectively) and at pH = 9.0 (93, 99, 93, 99 and 85%, respectively). The studies confirmed the high metal-complexing capacity of BSA and indicated that heavy metals might be effectively removed from wastewater containing protein in the process of membrane separation using a ceramic membrane.

Our paper presents a study on the middle reaches of the Ina River. Select physical and chemical indicators were analyzed in order to evaluate water quality. It was determined that the studied river was subjected to strong anthropopressure, and factors declassifying river water included CODCr, TP, general hardness, and alcalinity. A high level of biogenic elements was additionally increased by pollution discharged to the river in the proximity of a factory specializing in agricultural production and processing food and agricultural produce near the town of Stargard Szczecinski. The process of self-purification was noted, which can be considered as a factor modifying changes and dynamics of nitrogen and phosphorus in the studied river, leading to an internal enrichment with biogenic elements. Those processes were multi-directional as confirmed by PCA analysis, where component 1 accounted for just 36.7% of the total variance, and the total variance exceeding 90.0% was only noted for 7 components.

Background. Oxidative stress poses a serious threat to farmed fish, exemplified by depressed growth, decreased disease resistance, and reduced flesh quality. Therefore, the aim of this study was to examine differences in activity of antioxidant enzymes and concentration of selected biochemical parameters between blood plasma of both sexes of three species important for sustainable development of aquaculture: tench, Tinca tinca (Linnaeus, 1758); wels catfish, Silurus glanis Linnaeus, 1758; and sterlet, Acipenser ruthenus Linnaeus, 1758. Materials and methods. Experimental fishes were fed ad libitum for 60 days with a formulated diet (45% proteins, 20% fat, 16% carbohydrates, 8% ash and 2% fibre). At the end of the study venous blood samples were collected and 11 biochemical parameters were assessed: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), total antioxidant capacity (FRAP), alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), bilirubin, albumin, and uric acid. Results. Comparison between species revealed that the most significant differences were observed for tench and sterlet (in FRAP, GPx, CAT, GST LDH, ALT, bilirubin, and uric acid), less significant—for sterlet and wels (in FRAP, GST, LDH, AST, bilirubin, uric acid), followed by tench and wels catfish (in FRAP, GPx, GST, AST, and uric acid). Moreover, significant variations in the level of biochemical markers were also detected between sexes within each species, where the highest number was observed for tench (in FRAP, GPx, albumin, and uric acid), next wells catfish (in SOD, albumin, and bilirubin), and the lowest in sterlet (in ALA). Additionally, numerous differences in antioxidant potential (FRAP), antioxidant defence indices, as well as in markers of liver function, heart dysfunction, and markers of nutritional status were observed as species-specific and sex-specific. Conclusion. Results obtained in this study for the first time demonstrated species- and sex-related differences in plasma activity of antioxidant enzymes and concentration of selected biochemical parameters between tench, wels catfish, and sterlet reared in cage culture. The presented findings provide significant contribution not only to the existing knowledge of fish physiology but will also help to design optimal feeding practices to achieve sustainable cage aquaculture.

Nitrogen and phosphorus release during decomposition of Notothenia coriiceps (Richardson, 1844) fillets kept in seawater was examined in the laboratory. Amounts of N–NO2 −, N–NO3 −, N–NH4 +, total inorganic nitrogen, total organic nitrogen (TON), total nitrogen (TN), total reactive phosphorus, total organic phosphorus (TOP), and total phosphorus (TP) released during a 5-day exposure were measured. The highest average release (from the standard 100 g fillet wet weight) was typical of TON and TN (2.574 and 2.703 mgN dm−3, respectively) as well as of TOP and TP (1.526 and 2.648 mgP dm−3, respectively). The release was observed to be most intense during the initial 120 min of decomposition. As shown by the accumulation rate coefficient, the highest rate of nutrient accumulation in water was typical of organic forms of N and P (0.827 and 1.329, respectively). Organic nitrogen and organic phosphorus accounted for 94 and 54 % of TN and TP release, respectively. In the experiment, nitrogen and phosphorus were released from the fish remains with leached chemicals, which may form important chemical cues for scavengers.

The qualitative and quantitative composition of major ions and nutrient compounds in surface waters and soils of the west coast of Admiralty Bay (King George Island, West Antarctica) was investigated together with the effect of soil-forming processes and atmospheric precipitation on the ionic composition of surface waters. In the water bodies studied, Cl- and Na+ were dominant major ions (average concentrations: 1102.2 and 930.9 μM, respectively). Average concentrations of the other major anions ranged from 2.80 μM (F-) to 81.64 μM (SO42-) and major cations ranged from 12.46 μM (K+) to 130.76 μM (Mg2+). Average concentrations of total reactive phosphorus, N-NO2-, N-NO3- and N-NH4+ amounted to 1.374, 0.410, 6.299 and 1.490 μM, respectively. Average concentrations of Ca, Mg, Na, K, N and P in the surface layer of the soil equalled 16.8, 15.9, 6.4, 3.6, 0.646 and 0.744 g kg-1, respectively. The calculated Na+/Cl-, Ca2+/Mg2+, Ca2+/Na+ and HCO3-/Cl- ratios revealed that atmospheric precipitation was the main source of major ions. We conclude that the ionic composition of the waters of the western coast of Admiralty Bay differ from surface waters of Continental Antarctica.

Wastewater generated as a result of the fish brining process has a very high contamination load. Application of appropriate technologies of wastewater treatment in order to reuse it in the production process once the NaCl content has been supplemented can provide an alternative to its costly recycling. The experiment included ultrafiltration tests conducted on waste brine originating from food processing industry. The results of physicochemical tests indicated very high reductions of fat content (100%) and turbidity (99.8%). Reductions were also revealed in the case of other indicators, i.e., chemical oxygen demand, biochemical oxygen demand, protein and histamine content: by 24.4, 35.2, 27.6 and 22.7%, respectively. Furthermore, it was reported that the obtained permeate retained its quality and microbiological stability. The studied ultrafiltration (UF) process can be successfully used for recirculation of brine in salted fish processing, and at the same time constitute an easily monitored critical control point in the hazard analysis and critical control point (HACCP) system. Practical Applications Fish processing industry is characterized by very high water consumption for technological purposes and generates a considerable amount of wastewater burdened with organic matter and mineral compounds (mainly sodium chloride). Such wastewater is usually released to the common sewage system. An alternative solution would be to release it into a recirculation system. This solution can be made possible by membrane separation technologies. The application of the UF using ceramic membranes allows to obtain high-quality brine which can be successfully reused in the production process after the NaCl content has been replenished. Moreover, introduction of the UF technology meets the requirements of the HACCP system.

Fish farming and especially rearing and breeding of rainbow trout and carp is one of potential sources of surface water pollution. The study was aimed at assessing the effect of a rainbow trout farm on water quality in the Gowienica River in winter. Temperature, pH, electrolytic conductivity, total suspended solids, dissolved oxygen, BOD5, CODCr, alkalinity, water hardness, calcium, magnesium, ammonium-nitrogen, nitrate-nitrogen (III and V) and total phosphorus were determined according to Polish Norms and APHA [1995] in water samples collected in winter up- and downstream the study object. The increment of pollutant concentrations in rainbow trout farm effluents was referred to the requirements in Rozporządzenie MŚ [2006]. Performed studies and literature review show that effluents from the assessed fish farm did not worsen water quality of the river. Increased concentrations of total suspended solids and CODCr in effluents were noted only in March. According to data from the report on environmental status in zachodniopomorskie province in the years 2008-2011, poor water quality of the Gowienica River is recorded already upstream the rainbow trout farm. Pollution of this stretch of the river may originate from uncontrolled waste water management and from nutrient runoff from fields.

The study focused on the effect of iron and aluminium coagulants (PIX®113, PAX®18) commonly used for purification of open waters on key stages of embryonic development of pike (Esox lucius L.). Fertilized pike roe was incubated in lake water and in water with the admixture of coagulants, applied in the concentration of 50.0 mg dm-3 at selected stages of embryogenesis: blastopore closure, inoculation, and the hatching of larvae. In the course of the experiment, live embryos were observed and total lengths of the larvae were measured. Simultaneously, selected hydrochemical indicators were gauged. It was discovered that coagulants had the strongest effect at the first stage of embryogenesis (the end of the process of gastrulation). At that stage the survival rate of embryos was the lowest (73.5- 75.0%) and the percentage of deformities in the hatched larvae was the highest (9.7-10.0%).

Macro-ionic composition of fish opercula may be an indicator of the fish stock identity. This is especially interesting in river estuaries, where individual sections of the estuary may differ in terms of their hydrochemical regimes. Diversified macro-ionic tissue composition is likely to provide clues not only about the origin of an individual fish, but also about its possible migration routes. The current study researched this aspect of the chemical composition of perch collected from different sections of the Oder River estuary. A total of 60 European perch, Perca fluviatilis L., were obtained from 3 sampling sites located in the river at Widuchowa, Szczecin Lagoon, and Pomeranian Bay, where waters are subject to dynamic macro-ionic transformations. Fish length ranged from 20 to 25 cm. Opercula of the fish were examined for their content of calcium, magnesium, strontium, sodium, and potassium, with the aid of the flame method using a Perkin-Elmer 3100 atomic absorption spectrophotometer. Perch inhabiting the waters of the Oder River between Widuchowa and Szczecin Lagoon had their opercula composed predominantly of calcium. Calcium was also the predominant ion dissolved in the water in this area; Ca represented 83.6% of all cations in the water and 41.6% of those present in the bones of the perch operculum. The increased levels of salinity near the sea were associated with the replacement of calcium in bones by other, more readily available elements (magnesium or strontium). Differences in the observed macro-ion composition of the opercula were sufficient to assign the perch studied to two distinct groups inhabiting fresh and brackish waters.

Comparison of Biomass Growth in Microcystis aeruginosa Cultures Supplemented With Commercial Culture Mediums F2 and BG-11 In the study physiochemical composition of two commercial culture mediums, F2 and BG-11, used in the culture of microalgae and cyanobacteria was compared. Also influence of the medium on Microcystis aeruginosa growth has been evaluated. The following elements were determined in the culture medium: nitrite nitrogen, nitrate nitrogen, ammonia nitrogen, reactive phosphorus, and Redfield ratio. The increase of cyanobacteria was determined on the basis of chlorophyll "a" measurement. A substantial accretion in the cyanobacteria biomass growth was noticed in the culture supplemented by BG-11 medium, and the differences in its increase was statistically significant.